Transporting billions of goods and accounting for 90 percent of global trade, the global shipping industry has become an integral part of life in the 21st century and shows no sign of slowing down. However, such seaborne shipping comes at great human and environmental cost, especially for those who live along coasts and in port cities. Containing 3500x more sulfur than the diesel used for road vehicles, standard shipping fuel is responsible for 13 percent of total sulfur oxide emissions. Annually, 400,000 premature deaths from lung cancer and cardiovascular disease and 14 million cases of childhood asthma result as a direct consequence of ship-related pollution. However, researchers from the University of Delaware believe that by embracing greener fuels, the international shipping industry presents a great opportunity to significantly reduce global emissions and potentially save lives.

The study, which was published in Nature Communications in early February 2018, found that by switching to cleaner, low-sulfur fuels, the human health consequences of ship-related air pollution could be drastically reduced in just a couple years. The International Maritime Organization (IMO) has suggested that the amount of sulfur in shipping fuels be reduced from 3.5 percent to 0.5 percent. In the words of Natasha Brown, spokesperson for the IMO, “The reduction in the limit for sulfur in fuel oil used on board ships will have tangible health benefits, particularly for populations living close to ports and major shipping routes.” If such a change becomes standard, then by 2020 as much as a third premature deaths and over half of all childhood asthma cases caused by shipping-related air pollution may be prevented. In other words, 137,000 fewer deaths and 8 million fewer cases of childhood asthma will occur.

Despite this, researchers warn that simply switching fuels would not solve all of the shipping industry’s problems. Low-sulfur fuels of 0.5 percent will still be responsible for 250,000 deaths and 6.4 million new cases of childhood asthma every year, meaning that more aggressive standards will have to be implanted in the years following 2020 in order to further health benefits. Furthermore, reducing sulfur content would involve a climate change trade-off. Emitted pollutants from sulfate aerosols produce a radioactive cooling effect that helps keep global temperatures low. Reducing these aerosols could potentially exacerbate warming temperatures. With this in mind, the researchers suggest that a carefully balanced approach that takes into consideration both human health and environmental consequences is the best course of action.